HI,
How is your wife? What other symptoms are present? Pain may indeed be due to musculoskeletal issues including arthritis or neurological conditions also. Medical management and drinking plenty of fluids may help. If it persists, it is best that she sees her doctor for proper management. Take care and do keep us posted.
This pain in shoulder started about eight years ago when she gave birth to second child (daughter) thorugh surgery and next day of surgery she felt severe pain in her shoulder which gone away after few days but now this pain re-occur after one or two months specially in winter during handling of water. She is also complaining about increase in bleeding during periods since last one year.